Knocking sounds on start up

mine sometimes does that to :headscratch:

Sounds like its just a lifter loosing its prime after sitting for a bit.... Had a 4.6 thunderbird that used to do that, had almost 150,000 miles on it and i ran 15w40

What type of filter did you use? Check the oil and make sure the level is where it should be, its possible some leaked out or got burned off. There reason I ask about the filter is that the not-so-good ones don't have good valving. You're using the right weight of oil, but that noise needs to be addressed asap. If you have a crappy filter (pretty much anything other than purolator and wix) you might want to change the filter and see if that helps. Also, what type of oil are you using, brandwise? Synthetic or traditional?

i use a mobil 1 filter and mobil 1 Synthetic oil 5w-20

The oil is good, honestly don't know for sure about the filter, but I think its probably a decent one. Check the level to make sure its right, there are a bunch of things that could cause the noise, but if it started right after the oil change I would start by looking there, I don't believe in coincidences, especially with cars and noises.

I use motorcraft oil filter and 5w20 penzoil.